Published April 15, 2016 at 11:31 AM Updated April 15, 2016 at 11:34 AM

Five people have been arrested in Britain and several properties were being searched Friday in Birmingham in an investigation following the deadly attacks in Paris and Brussels, police said.

West Midlands Assistant Chief Constable Marcus Beale said the arrests aimed to address “any associated threat to the U.K. following the attacks in Europe.” The move comes only days after authorities in Belgium detained a suspect in connection with deadly attacks in Brussels and Paris who had ties to the Birmingham area.

Four people — three men aged 26, 40 and 59, and one 29-year-old woman — were arrested Thursday in the central English city of Birmingham. A 26-year-old man was also arrested Friday at London’s Gatwick Airport. The five were arrested for suspected ties to the commission, preparation, or instigation of acts of terror.

Police would not elaborate on the searches in Birmingham.

A week ago, Belgian authorities arrested and identified the “man in the hat” spotted on video alongside the two suicide bombers who attacked Brussels Airport on March 22, killing 16 people. The suspect, Mohamed Abrini, was also wanted in the Nov. 13 Paris attacks that left 130 people dead.

One European security official told The Associated Press that Abrini had made multiple trips to Birmingham last year, meeting with several men suspected of terrorist activity. The official spoke on condition of anonymity because he was not authorized to provide details about the investigation.

Surveillance had been taking place on suspected cell members in the Birmingham area since the Paris attacks, the official said.

A second European security with access to Belgian counterterrorism data said West Midlands police have closed in on a ring of suspects linked to Abrini’s phone after his recent arrest.

A Belgian judge on Thursday ordered Abrini and six other suspects arrested in connection with the attacks in Paris and Brussels kept behind bars for another month.

Belgian minister resigns after airport security criticized

Belgium’s transport minister resigned Friday after a secret European Union report detailing lapses in airport security oversight was leaked in the wake of the deadly March 22 bombings at Brussels Airport and subway.

Prime Minister Charles Michel said after his talks with Transport Minister Jacqueline Galant, “the minister presented her resignation to the King and the King accepted it.”

Galant said the leak was part of a vendetta against her by a disgruntled senior transport official and insisted that she always paid very close attention to security concerns.

The confidential EU document from last year was made public by two Belgian opposition parties. It called the oversight of security measures at the nation’s airports flawed and cited serious deficiencies in the way safety checks were managed.

The revelations came after the March 22 attacks in Brussels killed 32 people, including 16 at the national airport, and left 270 people wounded. The Islamic State group has claimed responsibility for the attacks.

Galant says she had not seen the EU report but Michel said “a summary of this report was discussed and sent to the minister’s cabinet in June 2015.”

No immediate replacement was named for Galant but Michel said he would do so as soon as possible.

The suicide attacks in the peak morning travel period have shaken the Belgian government, police and judiciary. The Belgian parliament has set up an inquiry to look into any shortcomings in the handling of the bombings. Belgium’s interior and justice ministers volunteered to step down last month, but their resignations were rejected.

“The government will work in perfect cooperation with the commission of inquiry so that all transparency can be ensured and to draw lessons for the future,” Michel said. “The security of all Belgians is a priority for this government.”

At a hastily organized press conference, a defiant Galant rejected allegations that she had been lax about security.

“If there’s an area I always paid attention to it’s that one,” she said.

She told reporters she is the victim of a “media crusade” organized by a senior transport official whose attacks on her would not end until she resigned. Galant accused her foes of “riding the current wave of worry” provoked by the Brussels attacks.

The EU carries out around 35 safety inspections at European airports each year. The restricted report, dated April 28, 2015, details shortcomings in the supervision of security in the Brussels Airport section that travelers enter once they have cleared security checks and around the planes themselves.

The suicide bombers blew themselves up in the departure area of Belgium’s main international airport, part of the facility that was not covered in the EU report.

Brussels Airport is one of the largest in Europe and a major European travel hub that handles 23.5 million passengers each year. It was shut down by the bombings for more than a week and has been struggling to get back up to capacity ever since.

An unannounced strike by Belgian air traffic controllers this week caused further transport chaos.